Some examples of wastewater treatment systems utilize biological and/or chemical reactions to remove or reduce harmful pollutants contained in the wastewater. These various biological and/or chemical processes desirably contend with multiple types of wastewater that enters the wastewater treatment system, for example, wastewater from industrial, commercial, and domestic sources. Problematic foam, grease, and other substances which are not well removed by the various biological and/or chemical processes may accumulate in the wastewater treatment system. For example, biological wastewater treatment processes often produce foam forming filamentous bacteria as a byproduct of the biological treatment process. These substances may create problems with regard to odor and appearance, and can impair settling of suspended solids in mixed liquor output from the biological treatment processes, as well as treatment efficiency.
In the past, some wastewater treatment systems have used pumps located at the lower portions of biological treatment tanks and/or at the bottom of a clarifier to waste excess biological growth from the treatment processes. These types of apparatus, however, have not been directed to removing floating materials from the various treatment vessels that may be present in a wastewater treatment system. More recently, some wastewater treatment facilities have installed surface wasting systems to remove problematic floating matter, for example, scum pipes, weirs, or skimmers. A significant disadvantage of these systems is that they remove well-settling organisms, in addition to the organisms that tend to float and cause foam. Further, these systems are typically not self adjusting and typically have inadequate flow control.